Process Control System, Apparatus and Method for Control of a Process Plant

Abstract

An apparatus and method for controlling a process plant in which a number of control processes are performed on common hardware, wherein encoded process variables are encoded in each of the control processes based on signatures that are defined individually in each of the control processes.

What is claimed is: 
     
         1 . An apparatus for control of a process plant, comprising:
 a control apparatus configured to implement a plurality of control processes on common hardware, each control process performing cyclic processing of at least one process value;   wherein the plurality of control processes each compute a first signature for the at least one process value and for carrying out the processing of the at least one process value using the computed first signature,   wherein the plurality of control processes each compute the first signature using a predetermined initial value and a cyclic increment; and   wherein each of the plurality of control processes defines at least one of initial values and the cyclic increment of the respective control processes individually.   
     
     
         2 . The apparatus as claimed in  claim 1 , further comprising:
 a storage facility which stores and provides at least one of the initial values and cyclic increments for the plurality of control processes on a remanent basis,   wherein each of the plurality of control processes, during a first initialization, determine the at least one of initial values and the cyclic increment and stores said determined initial values and the cyclic increment in the storage facility.   
     
     
         3 . The apparatus as claimed in  claim 2 , wherein each of the plurality of control processes, during a further initialization, determine the first signature using the initial value stored in the storage facility for at least one of a respective control process and a cyclic increment. 
     
     
         4 . The apparatus as claimed in  claim 1 , wherein each of the plurality of control processes newly determine at least one of the initial values and the cyclic increment during each initialization. 
     
     
         5 . The apparatus as claimed in  claim 1 , wherein each of the plurality of control processes compute at least one of the initial values and the cyclic increment of a respective control processes using a random value. 
     
     
         6 . The apparatus as claimed in  claim 1 , wherein each of the plurality of control processes compute at least one of the initial values and the cyclic increment of a respective control processes using at least one of a hardware characteristic and a software characteristic of the respective control processes. 
     
     
         7 . The apparatus as claimed in  claim 1 , wherein each of the plurality of control processes defines the cyclic increment in each cycle using a newly established random value. 
     
     
         8 . The apparatus as claimed in  claim 1 , wherein the plurality of control processes each assign to the at least one process value a second signature and to perform processing of the at least one process value using the computed first signature and the second signature; and
 wherein the second signature of the at least one process value is the same for all cycles of the cyclic processing.   
     
     
         9 . The apparatus as claimed in  claim 1 , further comprising:
 a data memory which stores process values of plurality of control processes and corresponding signatures for the process values;   wherein the control apparatus comprises a processing facility which implements the plurality of control processes.   
     
     
         10 . The apparatus as claimed in  claim 1 , wherein the plurality of control processes are each performed based on identical software code. 
     
     
         11 . A process control system, comprising:
 an apparatus for control of a process plant as claimed in  claim 1 ;   a plurality of field devices, which each comprise at least one sensor and/or actuator;   wherein the plurality of control processes of the control apparatus each at least one of (i) generate control commands using sensor values of the field devices and (ii) send control commands to the plurality of field devices.   
     
     
         12 . A method for control of a process plant, comprising:
 implementing a plurality of control processes by a control apparatus on common hardware, each control process of the plurality of control processes implementing cyclic processing of at least one process value; and   computing a first signature and processing the at least one process value using the computed first signature in each cycle for the at least one process value, the first signature being computed by a control process using a predetermined initial value and a cyclic increment;   wherein at least one of predetermined initial values and the cyclic increment of a respective control process is defined individually for each control process of the plurality of processes.